This invention relates to a process and apparatus for unloading melamine powder from a bulk container.
Up until now, the most usual and customary way to transport melamine powder was in the form of individual 25 to 50 kg. bags. Thus, transfer of large volumes of melamine powder could only be accomplished when many such bags were loaded onto pallets and placed in that form into a large shipping container. Additionally, for melamine of a quality that shows no "baking" properties, melamine powder has, at time, been transported in what have been referred to in the industry as bulk bags which are really 1500 kg. bags. (Intermediate Bulk Containers). AGain to ship large quantities of melamine powder a number of such bags would have to be loaded on pallets and shipped as are the 25 to 50 kg. bags.
As is evident such bagging procedures increase the production and transportation costs because of the bagging procedures that must be observed. Not only does bagging increase the cost of preparing shipments for transportation but in addition increase unloading costs since such shipments require more labor and time in unbagging procedures. In addition, any imperfections in the bagging procedure or any ripping of bags during the moving, loading, unloading of such bags can also result in certain losses of melamine powder. Each of these particular occurrences are not desirable and each of these problems is substantially eliminated by the present invention.
Certain known bulk melamine transport containers are also known but these are specially constructed tank trailers. These have been specifically designed and are useful only for transporting melamine and are not useful for transporting other substances or materials so that while trucks can transport melamine in one direction they are not available for carrying return freight and must deadhead back for another shipment of melamine. This is of course an inefficient use of trucks and substantially increases shipping costs.
By in large the most economical and efficient way of transporting melamine powder, specially for overseas transport, would be in the form of bulk cargo in trailer trucks or other large quantity containers, sometimes referred to as ISO-Containers.
Some melamine powders presently on the market exhibit better flow rates than other types but regardless, melamine is very fine and certain flow problems can result. Among these, are bridging which occurs when a quantity of melamine powder forms an arch or bride capable of supporting a quantity of melamine there above while allowing the melamine there below to fall away from beneath. Another problem characteristic of some melamine powders is rat holing where only a narrow flow opening occurs within a bulk supply of melamine powder so that the majority of the powder will not be flowing. Accordingly, certain problems can arise when trying to unload melamine powder from extremely large bulk containers. Further, it is not unusual for melamine to block the very means used to receive the melamine powder flowing from containers so that further transportation of melamine is not possible. Accordingly, it is not possible to pour melamine directly from a bulk container with only a funnel type of device for directing the flow of melamine powder.
Furthermore, it is not possible to dispense with a device for directing the flow of melamine, as this requires the presence of an expensive underground warehouse, and the flow of melamine from the container into the warehouse gives rise to much dust, loss of melamine and contamination thereof.